研究者詳細 - 永岡　勝俊

PubMed

Boosting Ammonia Synthesis under Mild Reaction Conditions by Precise Control of the Basic Oxide–Ru Interface

Sato Katsutoshi, Nagaoka Katsutoshi

Chemistry Letters 50 巻 ( 4 ) 頁： 687 - 696 2021年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：公益社団法人日本化学会

Strong basic oxide–supported Ru catalysts are easily prepared and handled, and they have been used as effective catalysts for ammonia synthesis under mild reaction conditions since the 1970s. Recent research has revealed that precise control of the boundary states between the basic oxide (i.e., rare-earth oxide, alkali earth oxide), oxygen defect sites, and Ru nanoparticles can be used to enhance ammonia synthesis under mild reaction conditions and inhibit hydrogen poisoning, which is a typical drawback of strong basic oxide–supported Ru catalysts.

DOI： 10.1246/CL.200855

DOI： 10.1246/cl.200855

Nonequilibrium Flow-Synthesis of Solid-Solution Alloy Nanoparticles: From Immiscible Binary to High-Entropy Alloys 査読有り

Kusada, K; Yamamoto, T; Toriyama, T; Matsumura, S; Sato, K; Nagaoka, K; Terada, K; Ikeda, Y; Hirai, Y; Kitagawa, H

JOURNAL OF PHYSICAL CHEMISTRY C 125 巻 ( 1 ) 頁： 458 - 463 2021年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Physical Chemistry C

Solid-solution alloy nanoparticles (NPs), where the constituents mix at the atomic level, show a variety of attractive properties due to their tunable electronic structures. However, it is still difficult to stably synthesize them, particularly nonequilibrium alloys that consist of combinations immiscible in the bulk. Here, we first report the successful syntheses of solid-solution alloy NPs including PdRu and PdRuIr, which are immiscible in the bulk, and of IrPdPtRhRu high-entropy alloy NPs through a continuous-flow reactor providing a high productivity with high reproducibility. The designed solvothermal flow reactor enabled us to use a lower alcohol as a reductant that cannot be applied in a batch synthesis for these NPs.

DOI： 10.1021/acs.jpcc.0c08871

Chemoselective hydrogenation of heteroarenes and arenes by Pd-Ru-PVP under mild conditions 査読有り Open Access

Chaudhari, C; Sato, K; Nishida, Y; Yamamoto, T; Toriyama, T; Matsumura, S; Ikeda, Y; Terada, K; Abe, N; Kusuda, K; Kitagawa, H; Nagaoka, K

RSC ADVANCES 10 巻 ( 72 ) 頁： 44191 - 44195 2020年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：RSC Advances

Monometallic (Pd, Ru or Rh) and bimetallic (Pd0.5-Ru0.5) alloy NPs catalysts were examined for the hydrogenation of quinoline. Pd-Ru alloy catalyst showed superior catalytic activity to the traditional Rh catalyst. The characterization of Pd0.5-Ru0.5 catalysts, HAADF-EDX mapping and XPS analysis suggested that the alloy state of PdRu catalysts remained unchanged in the recovered catalyst. Furthermore, the catalyst was highly selective for the hydrogenation of different arenes. This journal is

DOI： 10.1039/d0ra09981c

One-pot synthesis of pyrrolidones from levulinic acid and amines/nitroarenes/nitriles over the Ir-PVP catalyst 査読有り

Chaudhari, C; Shiraishi, M; Nishida, Y; Sato, K; Nagaoka, K

GREEN CHEMISTRY 22 巻 ( 22 ) 頁： 7760 - 7764 2020年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Green Chemistry

The synthesis of pyrrolidones via reductive amination of levulinic acid with aniline was examined over polypyrrolidone-stabilized metal nanoparticle catalysts. Among them, Ir metal was the most effective and applicable for the reductive amination of levulinic acid with nitroarenes/nitriles. Importantly, this catalyst was used for the one-pot synthesis of the anti-inflammatory drug indoprofen from 2-formylbenzoic acid and 2-(4-nitrophenyl)propanoic acid.

DOI： 10.1039/d0gc01725f

Oxidation of Ru/Ce0.5Zr0.5O2-x at Ambient Temperature as a Trigger for Carbon-Free H2 Production by Ammonia Oxidative Decomposition 査読有り

Coreduction methodology for immiscible alloys of CuRu solid-solution nanoparticles with high thermal stability and versatile exhaust purification ability 査読有り Open Access

Huang, B; Kobayashi, H; Yamamoto, T; Matsumura, S; Nishida, Y; Sato, K; Nagaoka, K; Haneda, M; Kawaguchi, S; Kubotak, Y; Kitagawa, H

CHEMICAL SCIENCE 11 巻 ( 42 ) 頁： 11413 - 11418 2020年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemical Science

This study provides a coreduction methodology for solid solution formation in immiscible systems, with an example of a whole-region immiscible Cu-Ru system. Although the binary Cu-Ru alloy system is very unstable in the bulk state, the atomic-level well-mixed CuRu solid solution nanoparticles were found to have high thermal stability up to at least 773 K in a vacuum. The exhaust purification activity of the CuRu solid solution was comparable to that of face-centred cubic Ru nanoparticles. According to in situ infrared measurements, stronger NO adsorption and higher intrinsic reactivity of the Ru site on the CuRu surface than that of a pure Ru surface were found, affected by atomic-level Cu substitution. Furthermore, CuRu solid solution was a versatile catalyst for purification of all exhaust gases at a stoichiometric oxygen concentration. This journal is

DOI： 10.1039/d0sc03373a

Matsunaga, T; Matsumoto, S; Tasaki, R; Ogura, Y; Eboshi, T; Takeishi, Y; Honda, K; Sato, K; Nagaoka, K

ACS SUSTAINABLE CHEMISTRY & ENGINEERING 8 巻 ( 35 ) 頁： 13369 - 13376 2020年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ACS Sustainable Chemistry and Engineering

Ammonia has received attention as a hydrogen carrier for energy use, and although ammonia decomposition can produce hydrogen at a high rate, there is currently no simple process for decomposing ammonia that is easily and rapidly initiated at any time without an input of external energy. Here, we report the discovery of a process for initiating and sustaining the production of hydrogen from ammonia without heating the catalyst externally. The oxidative decomposition of ammonia to produce hydrogen at a high rate was repeatedly triggered at ambient temperature (∼25 °C) immediately after NH3 and O2 were supplied to a Ru/Ce0.5Zr0.5O2 catalyst that had been previously reduced at ambient temperature. For this catalyst, active hydrogen atoms formed on Ru0 nanoparticles reduced Ce0.5Zr0.5O2 even at ambient temperature, and the very exothermic oxidation of Ce0.5Zr0.5O2-x as well as Ru0 heated the catalyst bed to the catalytic auto-ignition temperature for ammonia combustion, which was lowered by the contribution of mobile (active) oxygen over the Ce0.5Zr0.5O2. Oxidative ammonia decomposition was thereby triggered.

DOI： 10.1021/acssuschemeng.0c04126

Effect of Calcination and Reduction Temperatures on the Catalytic Activity of Ru/La0.5Ce0.5O1.75 for Ammonia Synthesis under Mild Conditions 査読有り Open Access

Ogura, Y; Asai, T; Sato, K; Miyahara, S; Toriyama, T; Yamamoto, T; Matsumura, S; Nagaoka, K

ENERGY TECHNOLOGY 8 巻 ( 6 ) 頁： 2000264 2020年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Energy Technology

Ammonia is a potential carrier of hydrogen as a zero-emission fuel. Herein, the effects of calcination and reduction temperatures on the ammonia-synthesis activity of Ru/La0.5Ce0.5O1.75 are investigated under mild synthesis conditions (≤400 °C, ≤3 MPa), which are the preferred conditions for the storage of hydrogen as an energy source. The highest catalytic activity is obtained after calcination of the support at 700 °C and reduction of the catalyst at 650 °C. Calcination using a higher temperature than that used for reduction results in the induction of a strong metal–support interaction (SMSI) effect. This high-temperature calcination also provides heat resistance to the support, which prevents sintering of the primary support particles during reduction. Thus, calcination and reduction at temperatures higher than those normally used for the preparation of Ru catalysts provide a novel approach for obtaining supported highly dispersed Ru catalysts exhibiting the SMSI effect and high catalytic activities.

DOI： 10.1002/ente.202000264

Surface Dynamics for Creating Highly Active Ru Sites for Ammonia Synthesis: Accumulation of a Low-Crystalline, Oxygen-Deficient Nanofraction 査読有り

Pr2O3 Supported Nano-layered Ruthenium Catalyzed Acceptorless Dehydrogenative Synthesis of 2-Substituted Quinolines and 1,8-Naphthyridines from 2-Aminoaryl Alcohols and Ketones 査読有り Open Access

Chaudhari, C; Sato, K; Ogura, Y; Miayahara, SI; Nagaoka, K

CHEMCATCHEM 12 巻 ( 8 ) 頁： 2198 - 2202 2020年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ChemCatChem

Pr2O3 supported Ru nanolayers and Ru nanoparticles catalysts were examined for the synthesis of quinolines. The Ru nanolayer was most active catalyst and showed a broad substrate scope. Structure-activity relationship demonstrated that the metallic state and morphology of Ru as well as the basic site of Pr2O3 were indispensable factors of this catalytic system.

DOI： 10.1002/cctc.201902311

Sato, K; Miyahara, SI; Ogura, Y; Tsujimaru, K; Wada, Y; Toriyama, T; Yamamoto, T; Matsumura, S; Nagaoka, K

ACS SUSTAINABLE CHEMISTRY & ENGINEERING 8 巻 ( 7 ) 頁： 2726 - 2734 2020年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ACS Sustainable Chemistry and Engineering

To mitigate global problems related to energy and global warming, it is helpful to develop an ammonia synthesis process using catalysts that are highly active under mild conditions. Here we show that the ammonia synthesis activity per weight of catalyst of Ru/Ba/LaCeOx, prereduced at 700 °C, is the highest among reported oxide-supported Ru catalysts, 52.3 mmol h-1 gcat-1 at 350 °C, 1.0 MPa. The turnover frequency of Ru/Ba/LaCeOx at 350 °C was more than 8 times that of Cs+/Ru/MgO, which is a well-known active catalyst used as a benchmark; furthermore, hydrogen poisoning, a typical drawback for oxide-supported Ru catalysts, was effectively suppressed. Scanning transmission electron microscopy observations with energy dispersive X-ray spectrometry and electron energy loss spectroscopy analysis revealed that a low-crystalline, oxygen-deficient nanofraction including Ba2+, Ce3+, and La3+ had accumulated on the Ru particles. This unique structure was obtained by exploiting the surface dynamics of alkaline earth compounds and thermostable rare earth oxides that contain redox-active atoms during the reduction at an unusually high temperature. The nanofraction showed strong electron-donating ability because of the strong basicity of the included cations, removal of carbonate, and formation of oxygen defect sites that eliminated electron-withdrawing O2- anions from the interface between the nanofraction and Ru atom. Electrons were therefore effectively donated to antibonding π -orbitals of the N2 molecules via Ru in contact with the nanofraction, and NN triple bond cleavage, which is the rate-determining step for ammonia synthesis, was promoted.

DOI： 10.1021/acssuschemeng.9b06299

Kinetics of ammonia synthesis over Ru/Pr2O3 査読有り

Imamura, K; Miyahara, S; Kawano, Y; Sato, K; Nakasaka, Y; Nagaoka, K

JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS 105 巻頁： 50 - 56 2019年12月

記述言語：英語掲載種別：研究論文（学術雑誌）

We investigated the kinetics of NH3 synthesis over a catalyst consisting of low-crystalline Ru nano-layers supported on Pr2O3. We determined the reaction orders with respect to N2, H2, and NH3 at various temperatures and pressures over Ru/Pr2O3, as well as Ru/CeO2 and Ru/MgO. The reaction orders with respect to N2 were always almost unity for all the catalysts under all the reaction conditions, indicating that the rate-determining step was NN bond cleavage. In contrast, the reaction orders with respect to H2 differed among the catalysts and decreased with increasing pressure and increased with increasing temperature. Under all conditions, the reaction order with respect to H2 was largest over Ru/Pr2O3 and smallest over Ru/MgO, indicating that hydrogen poisoning of the Ru surface was retarded to a greater extent over Ru/Pr2O3 than over Ru/MgO. In agreement with the trends of the H2 reaction orders, the NH3 synthesis rates over Ru/Pr2O3 at 400 °C rose drastically (64 mmol h−1 g−1) as the pressure was increased from 0.1 to 3.0 MPa. Furthermore, decreasing the feed gas H2/N2 ratio at 3.0 MPa effectively increased the NH3 synthesis rate over Ru/Pr2O3, which reached 45 mmol h−1 g−1 at 350 °C at a H2/N2 ratio of 1/0.5.

DOI： 10.1016/j.jtice.2019.10.006